Empire of the Air Part 2 – R.100 Overseas

Whilst we in LR have generally been bound to the ground or under it, we once again turn our eyes up to the skies. The Imperial Airship Service was a very serious scheme authorised at the highest level of British government, centred on London and intended to span the globe. We looked at the genesis of this programme in Part 1.

To remain competitive with the growing American economy, Britain sought better and closer communications with its Empire. The Imperial Airship specification issued in 1925 was for two airships to fly 100 passengers and 62 tonnes of cargo between London and:

• Canada non-stop in three days
• India in six (with a refuelling stop)
• Australia in ten (with multiple refuelling stops)

The Capitalist Airship – R.100

The specification pitted the private firm Vickers against the government’s Royal Airship Works. The fixed price contract for the R.100 was awarded to Vickers because of their recent history designing the R.80. Vickers set up a subsidiary, the Airship Guarantee Company, to design and build the airship in Vickers’ twin airship shed in the small town of Howden, Yorkshire, with Barnes Wallis leading the design.

Capitalist innovation – Barnes Wallis

To greatly simplify assembly and reduce labour costs, Barnes Wallis developed new structural design techniques on the R.100, building her from only nine standard and 50 other parts, whilst using as little machinery as possible. The ship was designed with only 13 longitudinal girders, compared to previous designs of up to 25, greatly saving weight.

The R.100’s hull was composed of a lightweight duraluminum alloy structure made up of rings and longitudinal beams, internally braced with kilometres of metal wire like the taut spokes of a bicycle wheel. Additional wires were used to tighten the cover over the hull, causing the concave shape between the longitudinal members, but this allowed the skin to flap (safely) at high speeds. However, any hydrogen that escaped from the airbags was released directly outside the envelope.

In contrast, the R.101 had a pressurised space between gasbag valves and envelope which kept the outer cover smooth and more aerodynamically efficient. Although this space was vented, it often contained a hydrogen-air mixture.

The R.100’s design also used internal wires to hold the gasbags in place, as well as Zeppelin type gasbag valves to prevent the hydrogen over-expanding as altitude increased. This could also occur with a sudden change of atmospheric pressure, such as what happened to the USS Los Angeles at her mast when a sea breeze of colder, denser air blew in, which raised the ship vertically.

Nevil Shute Norway was the Chief Calculator on the R.100 design team. Calculators were the human computers of their day, and he and his team computed the stress and aerodynamic forces on the components, materials and structure. Dropping his surname for his nom de plume, Neville Shute is better known today as a novelist, but his autobiography Slide Rule contains considerable detail on the design and flight of the R.100.

Catching up and surpassing the competition

After the Great War, the Zeppelin Company was beholden to the restrictions to German air fleets under the Treaty of Versailles. Specifically, the Treaty forbade the fabrication of airships with more than 30,000 cubic meters of gas, and effectively removed the ability of the Army to fund aviation projects. These prevented the development of airships in the 1920s. The Zeppelin Company had to diversify to other fields, such as car manufacturing and industrial castings. 

This allowed Britain’s Imperial Airship Service to catch up to their German competitor, and build the two new ships larger than anything the Weimar Republic had built to that point. However, the Zeppelin Company realised that Germany still owed the United States an airship as a war reparation. So the company convinced the government to order a Zeppelin airship for the US, which had the bonus of revitalising airship production. The firm applied its expertise to a new model of airship, with the delivery of LZ126 to Lakehurst in October 1924 (flying over New York). This was a public relations success, and paved the way for regular Germany – USA Zeppelin flights a few years later

The delivery coincided with a technology sharing agreement between Zeppelin and the US Goodyear Co. This involved high-stress cross-sectional girder design, and the effective expansion of Zeppelin capacities, both of which led directly into the Hindenburg Class airship. In addition, one of the chief Zeppelin designers migrated to the US at this time, where he also assisted the US Navy with its airship designs. One such airship, USN Akron, had five scout planes attached for coastal patrols.

We covered the flights of Germany’s next ship Graf Zeppelin LZ127 in Part 1. Nonetheless, British airship innovations continued apace.

British technical innovations

Barnes Wallis later refined his structural approach into his geodetic lattice aircraft frame that culminated ‎in his famous Wellington bomber during World War 2. Later in the war he designed other armaments such as the dambuster bomb, and afterwards he developed the first practical swing-wing aircraft design in the 1950s.

The Vickers ship was put through an independent design review as per the proper engineering process and did not require major rework, which is testament to her robust design. The R.100’s first flight was on 16 December 1929, and on subsequent flights she became the fastest airship to date, reaching 81mph, although the specification only called for 70mph. And she had a disposable lift of 57 tons, close to the specified 62 tons.

The contract for the R.100 called for a final acceptance flight of 48 hours and a demonstration flight to India. This flight was changed to Canada as petrol vapour ‎was believed to be too volatile for the hot tropics.

In January 1930 her construction was completed and she was flown to the Royal Airship Works at Cardington. There Chief Vickers designer Sir Dennistoun Burney managed to obtain a contract for a follow-on preliminary airship design from the Air Ministry ‎to keep his experienced design staff together pending flight trials and initial deployment for the two dirigibles, and Parliament’s direction for the Imperial Airship Service.

The R.100 undertook 54 hours of flight trials over England and the Channel. Flying an airship is a lot less work than handling it on the ground, as the old Royal Naval Air Service (RNAS) adage stated that the only way to get a rest in the airship business is to take the ship into the air.

The R.100 ended up slightly shorter than initially constructed – her pointed tail had to be rounded to a nub as a result of unexplained tail pressure during flight trials.

The Socialist Airship – R.101

The Government, in contrast, spared no expense on the development of the R.101, as befitting the intended showpiece and flagship of His Majesty’s Airship Fleet. Amazingly however, the same team of officials and engineers involved with the ill-fated R.38, which had folded in half in flight and crashed with heavy loss of life, was allowed to design and build the R.101.

The Royal Airship Works’ R.101 development was supported by substantial research conducted by universities and the National Physical Laboratory (NPL), as well as using the state owned R.33 (sister ship of the R.34, which had flown the first east to west Atlantic crossing in 1919) to test concepts and designs.

One of either R.33 or R.36 was planned to be flown to Egypt to conduct hot weather flying tests, but the delays in designing the current airships’ innovations meant that only R.33 was recommissioned, but only flown locally.

Socialist airship innovation

To save weight and maximise manoeuvrability, the engines of R.101 were fitted with light, hollow variable pitch steel propellers. ‎However, they could not withstand the diesels’ vibrations, so fixed pitch wood airscrews had to be used. This resulted in the R.101 not being able to reverse at the mast, so one of her five engines had to be dedicated solely to reversing, preventing full speed testing. For the airship’s first service flight, the camshafts of two engines were modified to be able to run in reverse.

The R.101 oddly had the wireless and navigation room within the airship body, and the main control cabin 20ft below it. Not ideal in a crisis. This was different from the R.100’s simpler single control car attached under the airship, which kept all critical control and communications functions together.

As no internal wire bracing was used in R.101, the frame structure had to be wider to provide the same strength, so it extended further into the envelope, which limited the size of the gasbags and therefore disposable lift.

The main ballast tanks were connected by pipes so that water ballast could be transferred with compressed air from one to another to adjust the ship’s trim. Most of the tanks could be operated remotely from the control car, except the nose ballast. The ballast tanks could also be filled with fuel if need be.

Rather than use the state of the art Zeppelin gasbag valve, R.101 designer Michael Rope devised new valves which appeared to work well, although they sometimes let out gas intermittently when the ship rolled in gusty weather.

The R.101 was deliberately designed with smaller fins than her rival, for optimal stability and control at cruising speeds, and lower weight. But at slower speeds this meant she was sluggish, whereas her rival exhibited much finer control at all speed and flight regimes.

Bizarrely, the R.101 even featured an asbestos lined smoking room, despite the risk of a catastrophic explosion from even the smallest unconfined fire.

Problematic cover

To decrease manufacturing times, the R.101 team had experimented with pre-treating the linen cover, but this resulted in a very weak fabric, referred to in some contemporary accounts as ‘rotten’.

The completed R.101 was 777ft long, but was 23 tons overweight, and her gas bags were quite leaky. Furthermore, as a government showpiece technology she was often pulled off flight trials to appear before the public, such as for a flypast at RAF Hendon.

Unlike the R.100, there was no independent design review of the R.101 design to identify potential problems.Despite this being a widespread engineering standard principle by this time, as designers and engineers are less likely to note faults in their own work.

Due to the politically imposed deadline of flying by early October 1930, this left untested much of the flight envelope and capability in adverse conditions.

Parallel designs proceeding apace

From the start there was a rivalry between the R.100 and R.101 design teams, but the Government team was given every advantage, the resources of Government technical, engineering and scientific ministries and departments. This enabled the development policy of extensive research into the design of all components. The capitalist team had to tough it out with its own technical resources, so consequently used many proven off the shelf designs and technologies.

Each ship’s gasbags were filled with about 5 million cubic feet of flammable hydrogen. The United States had the global monopoly on non-flammable helium, another lighter-than-air gas, but the US didn’t sell it in large quantities, considering it a strategic asset. Helium at the time was so scarce – the USS Shenandoah needed 2.1m cu.ft, which was then most of the world’s available reserves – that the USS Los Angeles had to use the Shenandoah’s gas for its initial flights.

One way competition

The R.101 team knew all about the R.100, as the Air Ministry had mandated that Vickers had to send their wind tunnel and structural test data to the Government aerodynamics data office, which was thence sent to the Royal Airship Works R.101 design team at ‎Cardington.

However, the converse was not true – the only information the Capitalists obtained on the R.101 came from newspapers or public events. But this had a hidden benefit – Vickers held their cards close, so were free to innovate and discard ideas away from public scrutiny, whereas the Government team was pride bound to make their designs work once they had been made public.

The R.100’s faster speed was a sore point at the Royal Airship Works, as the government airship designers could not believe that their competitor’s ship was 10mph faster and had 20 tons more disposable lift than their R.101, which had the full scientific and engineering resources of the Government behind it.

Engine problems

Given the goal for the airships to span the globe, the capability to fly in tropical conditions was essential. As petrol gives off a vapour that has a dangerously low flash point at high ambient temperatures, alternate fuels were investigated.

The Air Ministry originally mandated both dirigibles to have large Beardmore diesel engines running on a hydrogen-kersosene mix, the idea being that the hydrogen provided lift until used.

The Beardmore diesels had been designed for use in Canadian railcars, but were still in development, and as built they were much heavier and not as powerful as anticipated. Furthermore they proved very troublesome to maintain, so the R.101 could rarely be tested at full speed or at the edge of her performance envelope.

Despite much time and design effort, the Royal Airship Works eventually gave up on making the fuel mix work satisfactorily and used the engines with straight diesel. Still, its five engines weighed 20 tons, twice the weight of the R.100’s engines.

Furthermore diesel engines were thought to be the future aviation engine of choice due to their higher energy density and greater fuel economy. This was especially important on long distance journeys. Diesel was also much cheaper, £5 a ton, versus £23 a ton for petrol.

However, Vickers quickly determined that these Beardmore engines were far too heavy for the power they produced. After quietly observing their competitor’s engine problems, Vickers saved both money and mass by ‘temporarily’ substituting second-hand Rolls Royce Condor petrol engines instead. These were proven, trouble-free, and easy to maintain Rolls-Royce Condor petrol motors in place of the Beardmores. The R.100’s 6 engines totalled about 10 tons, half the weight of her step-sister’s motors.

Different risk approaches

Vickers, having their own money on the line as they were already over budget, regarded the airship’s engineering as the highest risk, so proceeded with development and testing accordingly. Furthermore, Vickers had an eye on future orders, with its own aviation reputation on the line, so the company was much more careful to rigorously stress test their ship.

In contrast, the Air Ministry believed that the political risk of the Imperial Airship Scheme’s survival was paramount. They had also assumed that the Royal Airship Works designers and engineers would perform their jobs to high British technological and engineering capabilities, not realising that the political requirements ate into the engineering focus and flight test time .

Despite these differing risk approaches, these two dirigibles were still essentially experimental prototypes trialing new designs with untested technologies, using an extremely flammable levitation ‎agent.

The Air Ministry and its Secretary of State had blind faith in the Government’s technical resources and staff, and moreover in their own ability to bend men and nature to their will. Pride, as with the Titanic, as well as playing with flammables, could be tragic flaws.

R.100 completed

The initial flight of the R.100 was on 17th December 1929, with construction being completed on 10th January 1930. Vickers put the airship through full speed and adverse condition stresses in a rigorous test program, and after seven successful trial flights they determined that the outer fabric cover was a potential weak point in the design. But this was not considered a current risk.

Luxury light

As befitting Imperial flagships, both dirigibles were luxuriously appointed to near First Class steamship standards. Their interior passenger spaces were completely new to airship design, replicating the dining rooms of their competitors, large ocean liners, to attract the same type of moneyed customers in a mostly open plan. On each ship a double staircase led down from the passenger cabins and mezzanine.

The outer side of the accommodations were flanked by large panoramic windows providing the two level 40-foot wide promenade deck with a large, open and light feel. Only the need to save weight compromised the detailing and materials used, such as wicker furniture.

Accommodations were spread over the R. 100’s three decks, the lowest for crew only. The R. 101 had two levels, but with a fully equipped galley on the lower deck and a dumb-waiter lift to the dining room.

Lord Thompson returns

As soon as the Labour government returned to power in June 1929, Lord Thompson took up his former position as Secretary of State for Air and declared that he would take the R.101 to India and back before the Imperial Conference in London in October 1930. He visited the Royal Airship Works as often as his Government schedule allowed, sometimes taking the Bedford train, to fly on as many R.101 test flights as he could.

‎Thompson wrote to a confidant that he had yet to return to the place of his birth, India, and what better way to see the Ganges than “from the prow of this almost mythical ship”.

Lord Thompson had dictated a safety first approach in the R.101’s design, but only apparently in the innovations to reduce or eliminate known risks to airships – structure, hydrogen lifting agent, diesel engines, and not in engineering or operating procedures that would interfere with his own joy in flying on board, nor the carriage of influential personages to advance the Imperial Airship Scheme.

Test flights as political capital

On her very first flight, the most senior Royal Airship Works staff ‎and top officials of the Air Ministry, including Lord Thompson, were on board the R.101, which passed over London. Unthinkable nowadays, but common at the time. Even the Graf Zeppelin carried fare paying passengers on only it’s seventh flight, although she was not nearly as experimental as the British ship. ‎

Nonetheless, for short trial flights, as many dignitaries and influential people were taken on board as was physically possible. On the R.101’s fifth flight, 40 passengers were provided a three hour joy ride, including officials from the Aeronautical Research council, the Admiralty, the National Physical laboratory, the Post Office, the Royal Aircraft Establishment, and the Treasury to help build support for the scheme across the civil service. The ship had only three of five engines operational, and low pressure and rain conditions only invited problems. Fortunately she flew well.

The Secretary of State Lord Thompson often worked on board, at the mast and in flight, which he declared was more peaceful and productive than his Ministry office. He even tried to convince his Cabinet colleagues to have a Cabinet Meeting on board, but fortunately having all of the Government’s senior Ministers working right under 5m cubic feet of very flammable hydrogen was not to pass.

On a subsequent test flight, many MPs and the Director of Civil Aviation ‎were taken aloft, with 159 MPs on the waiting list. Almost every test flight carried politicians and people of influence. Even on a test run cancelled die to bad weather, some MPs got themselves so drunk on board that they were convinced they’d actually flown, as the engines were still operated to provide heating.

Imperial Airship Scheme realises limitation of current fleet

The gas bags on both ships were leaky. Over a two month period, the R.101 had to be refilled with the equivalent amount of hydrogen that she carried, almost 5m cubic feet. Her step-sister lost almost as much over her longer flight test period.

‎With the realisation of being heavier than designed and with lower disposable lift, it became clear that the two step sisters would not satisfy the initial requirements. To address this shortcoming, ‎the concept of adding additional refueling stops at Malta, Basra, Baghdad, or Bahrain, came about to allow the required commercial loads to be carried to Egypt and India.

These ships are not enough

The Royal Airship Works undertook a design study based on Empire airship development to February 1929, which determined that the dirigibles as originally constructed would not meet the operational requirements.

	R.100	R.101	Specification
Range with payload of 6,720 lb (3 050 kg)	4,095 miles (6 590 km)	2,585 miles (4 160 km)	3,590 miles (5 780 km)
Endurance	64 hours	42 hours	57 hours
Disposable Lift	54 tons	35 tons	62 tons

First overseas Imperial Airship Scheme base

Canada became involved in the Imperial Airship Scheme during the 1926 Imperial Conference, when Canadian Prime Minister Mackenzie King pledged Canada’s assistance to the mother country. The Canadian goal was more for increased trade than Imperial duty, as well as ensuring that the British airships came to Canada and not only New York. Of all the Dominions, only Canada and South Africa showed interest in the Airship Scheme – the UK Air Ministry’s well-rehearsed presentation failed to convince the Australian, New Zealand, and Irish governments to build airship infrastructure or contribute funds.

Canada quickly approved construction of an airship base, airport, and mooring mast. Royal Airship Works experts came over in May 1927 to choose a site, settling on farmland on the south shore of Montreal at St-Hubert, and work began almost immediately. That summer the Air Ministry decided to send the R.100 to Canada, and the R.101 to India. A small team from the Royal Canadian Navy spent eighteen months training at the Royal Airship Works on proper airship ground handling.

Empire demonstration flights – Preparation for commercial service

To work up to a commercial service, the R.100 was planned for a series of midsummer flights to Canada, to avoid the often blustery ‎non-summer seasons. As well, she was pencilled in to fly to Egypt in the cooler months between October and March.

Similarly her step-sister was planned to fly to India after September and before April, to avoid the hottest months there that would reduce her disposable lift by as much as 11 tons.

It was hoped that regular monthly commercial flights to Canada and to Egypt could be started within the year. To be commercially successful however, the Royal Airship Works deemed that a minimum on time service measure of 85% would be required. This would require higher average speeds and more reserve fuel being carried on every voyage.

Nevertheless, the inaugural Empire flights of each airship were in effect a fly off competition, similar to what competing aircraft designs go through.

First Empire demonstration flight – Canada

After a domestic flight program by each ship, the Imperial Airship Scheme’s first major test was an Atlantic crossing to be made by the R.100. She departed for Canada on 28 July 1930, with 42 officers, engineers and crew aboard, but only two passengers. The ship flew over Ireland, the Atlantic, and Newfoundland, arriving Montréal three days later, having covered the 3,364 mile distance in 78 hours and 49 minutes, half the time it took by steamship then train.

An interesting experiment

As the R.100 crossed the Atlantic, the captain stuck his rubber-gloved hand out of the window, holding a round piece of glass.

Every three hours during the trip, this was repeated by Squadron Leader Ralph Sleigh Booth or another crew member, for five minutes at a time.

A couple hundred feet below, a passenger on a steam ship heading in the same direction, Lester Dillon Weston, watched through a telescope. Booth was carrying out an experiment aimed at ensuring the human race could continue to feed itself. The piece of glass was a Petri dish designed to pick up spores released by a fungus known as wheat rust, which had destroyed large areas of crops in North America.

Cambridge University scientist Dillon Weston, who was also keen on aviation, wanted to find out whether spores could cross the Atlantic. The R.100 provided the ideal platform for his research.

The government had spent five years and plenty of money on the Airship Scheme, and the public was becoming impatient for ‎results. This experiment would provide great publicity for the flight, so the captain agreed to participate.

The dirigible voyage fortunately coincided with Dillon Weston’s trip to Canada for a year-long study of the effects of fungi on crops. Dillon Weston watched a small portion of the flight from the Ausonia below, but the 64mph cruising speed of the R.100 was far greater.

When he arrived in Canada, Dillon Weston collected the Petri dishes to analyse, for what he thought was the start of a series of experiments. However, he never wrote a full report, as he considered the evidence gained from the R.100 inconclusive on the movements of wheat rust spores.

Arrivée au Québec

Despite their very large size, airships do not roll, except in very turbulent weather. As the R.100 approached Québec City she had inadvisedly entered a severe storm, and was buffeted by severe shifting winds she had never experienced over England or the Atlantic. A number of very large tears appeared on three fins, but airships are unique in that most cover repairs can be made whilst in flight. Riggers perched perilously in mid-air for eight hours to make repairs.

The voyage to and from Canada was so smooth, excepting this storm, that the crew regularly played the gramophone without it skipping. One crew member reported the quiet and virtually vibration free ride as “one of total exhilaration”.

There was also a small cockpit at the top of the bow for taking navigational sextant sightings. A walkway extended along the top of the ship to the rear of the fins, with a rope handhold alongside, to another hatch. Neville Shute wrote:

“…personally I always went from bow to stern because the rush of air pushed you up the first climb and you didn’t have to look down. When the ship was cruising at about sixty miles an hour, as soon as you got to the top, or horizontal, part of the hull you were in calm air crawling on your hands and knees; if you knelt up you felt a breeze in your head and shoulders. If you stood up the wind was strong. It was pleasant up there sitting by the fins on a fine sunny day, and whenever I went up there I would usually find two or three men sitting by the fins and gossiping. We kept a watch up there in daylight hours to keep a eye on the outer cover, and the ‎riggers got so used to it that they would walk upright along this little catwalk with their hands in their pockets, leaning against the wind and stepping over my recumbent body as I crawled on hands and knees. Burney lost his watch up there one evening; it lay on top of the ship all night and was found by one of the riggers at dawn the next day, and returned to him…You could climb all over every part of it in flight and carry out any repairs or maintenance that might be necessary.”

Neville Shute Norway

Shute related some other light-hearted moments in his book that were not disclosed to the press of the day. In case tears occurred in the outer cover, ‎a five gallon drum of red dope had been brought along to make repairs, which varnished and waterproofed the linen cover. Unfortunately, after repairing the fins over Québec, the crew left the barrel open. A sudden gust had plunged the ship’s nose down slightly, which spilled red dope into the control car like dripping blood. After the initial ‎shock, the flight deck soon realised the non-mortal origin of the fluid.

Then in the evening as the ship approached the lights of Montréal, the crew saw an enormous fiery red cross ‎floating above the city, which held them all transfixed and speechless, until someone said “That’s not Montréal. That’s the New Jerusalem. This is it, boys!”

What none of the crew knew was that the French province of Québec was staunchly Roman Catholic, ‎and the church had erected a 100 foot high Cross with steel girders and festooned with red lights atop Mount Royal, a mountain near the centre of the city.

Despite these two red omens, the R.100 successfully continued, and once daylight came she floated again over the city, welcomed by carhorns and blowing whistles.

The Canadian Broadcasting Corporation (CBC) had their famous hockey announcer, Foster Hewitt, host the live radio broadcast. The public euphoria was such that La Bolduc, Québec’s first folk singer/songwriter, wrote << Toujours L’R-100 >> (“R.100 Forever”) about the airship’s arrival.

The only landing in Canada was at the airship mast at St-Hubert. Over 250,000 excited spectators greeted the ship on its arrival, and over a million came to see her over its 12 day stop in the Dominion, as well as the Canadian Prime Minister and senior Canadian government officials. Three thousand toured the dirigible’s passenger spaces, braving the half-metre gap between the airship’s gangway and the mast’s slightly mis-specified p‎assenger deck, which gave quite a scare to many visitors.

During this stay Burney and Air Ministry representatives held ten meetings in Montreal and Toronto promoting the virtues of airship travel, greater Imperial co-operation, and trade.

During the visit, British officials suggested that Canada (on their own dime) build an airship shed at St-Hubert, a second mast on the Atlantic coast. Specifically, The Royal Airship Works had recommended construction of an auxiliary mast at St John’s, in the then-British colony of Newfoundland, or in Moncton, New Brunswick, as a backup base. Plus another mast in Vancouver on the west coast, which could open routes to Japan, China, and Australia. The Canadian government held a wait and see attitude.

After making more substantial repairs to her cover in St-Hubert, the R.100 then took a 24 hour scenic flight over central Canada, carrying passengers gracefully over Ottawa, Toronto and Niagara Falls. A “mass of humanity” of over 100,000 watched at the Toronto waterfront as she passed overhead. Work stopped, traffic ground to a halt, and rooftops were packed as everyone strained to glimpse the pride of Great Britain. The ship was the largest vessel most had ever seen. Commander Booth ordered the nose dipped in salute, intentionally, as she flew over, and the crew were seen waving to well-wishers on the ground.

After picking up 13 journalist passengers in Montreal, the R.100 headed back to England. Many Canadians expected to see her return within a few months. Due to water leakage from rips in the cover midflight, the R.100’s electrics were shorted out, meaning cold meals and tea for the rest of the flight. All flight commands had to be passed by the bac‎kup speaking tube system.

Even though one engine had failed, the return trip to England took only 57 hours 56 minutes thanks to the Gulf Stream. Upon her return from Canada, the R.100’s co‎ver was determined to be sufficiently stressed to require its complete replacement, as well as repair or replacement of her increasingly leaky gas bags.

Nonetheless, the R.100’s return trip was seen as a great success, heralding the future of air travel.

Not meeting spec

After her return, the magazine Air objectively stated the limitations of the R.100:

• She carried only two passengers and no payload on the westbound flight against the prevailing winds.
• She had only 6 hours of fuel at full speed remaining upon docking in Montréal.
• Only two crew watches could be carried, not the recommended three.
• Riggers on board were almost constantly busy repairing various rents in the envelope, at one point having 15 men on the outside of the ship.
• Had a cover tear been larger it could have disabled the airship or forced a crash landing, with possibly catastrophic consequences.

Another journal of the day was quoted as saying “Evidently we have still a good deal to learn about the design, construction and management of big airships”, which is an interesting counterpoint to the opinion of the Royal Airship Works the year before that large airship design was mature. The journal went on to note that the R.100 provided comfortable travel in weather that would not nearly be as agreeable in a steamship.

In Part 3, we will look at the R.100’s sister ship’s Imperial flight.

This article is dedicated to the Royal Patron of London Reconnexions, Lord Dawlish, whose erudite version of English is used herewith to provide an approximation of the language and spelling in use during the Imperial Airship period.